Biomedical subjects

Norbert Pallua

Publications and source records attributed to Norbert Pallua.

At least 19 recordsLinked to original sources

PubMed2006

Human serum from platelet-poor plasma for the culture of primary human preadipocytes.

In adipose tissue engineering, the use of human serum is essential to achieve the goal of an autologous system. Serum from conventional human plasma (SCP) contains platelet-derived growth factor (PDGF), a growth factor known to be both a potent inhibitor of adipose differentiation and also the most important stimulator of proliferation in human serum. Serum from platelet-poor plasma (SPPP) is considered to be PDGF-deprived and should therefore inhibit the differentiation of preadipocytes to adipocytes to a lesser extent. Effective cultivation of preadipocytes with SPPP requires compensating for the missing stimulatory PDGF effect on proliferation. However, the addition of other growth factors to the media needs to provide stimulation of proliferation without significant inhibition of differentiation. Primary human preadipocytes were isolated from adipose tissue samples of 10 healthy human donors and cultured under four different medium conditions (SCP, SPPP, SPPP + 1 nM basic fibroblast growth factor [bFGF], and SPPP + 1 nM epidermal growth factor [EGF]) for five generations. Proliferation activity and differentiation capacity were assessed for each sample, generation, and culture condition by calculating doubling time and measuring glycerol-3-phosphate dehydrogenase (GPDH)-specific activity. The use of SPPP resulted in a marked rise in GPDH activity compared with the cells cultured with SCP. Supplementing SPPP with 1 nM bFGF or EGF increased proliferation activity significantly. SPPP can be considered superior to SCP for the culture of primary human preadipocytes in adipose tissue engineering in terms of proliferation activity and differentiation capacity.

Adipocytes↗

PubMed2006

Efficacy and safety of polyacrylamide hydrogel for facial soft-tissue augmentation in a 2-year follow-up: a prospective multicenter study for evaluation of safety and aesthetic results in 101 patients.

BACKGROUND: Polyacrylamide (Aquamid) is a nonabsorbable soft-tissue filler. It consists of a polyacrylamide hydrogel. Safety and aesthetic results after injection of polyacrylamide hydrogel for facial soft-tissue enhancement were analyzed in a clinical trial. METHODS: In a prospective multicenter study, 251 patients were enrolled for injection of polyacrylamide hydrogel (Aquamid). The results of the first year follow-up have been described previously. One hundred one of 251 initially enrolled patients could be recruited for follow-up 24 months after the first injection. Standardized photographs were taken, and blood and urine samples were collected before treatment and during follow-up visits. Common sites of injection were nasolabial folds, lips, glabella folds, and other sites. The amount of injected gel ranged from 0.2 to 12 ml. RESULTS: A course of 24 months was followed in 101 patients. Results were judged to be good or very good by the investigators in 93 patients. Eighty-six patients judged the aesthetic outcome as satisfactory or very satisfactory. No severe side effects were observed during the 2-year follow-up period. Transient local reactions that resolved spontaneously were detected in several patients. In one case, burning sensations after lip augmentation were reported lasting up to the 24-month follow-up visit. CONCLUSIONS: Polyacrylamide hydrogel (Aquamid) yielded satisfying aesthetic results in more than 90 percent of patients. There was no difference in efficacy between 12 and 24 months' follow-up. No adverse soft-tissue reaction was observed. The study group may be biased, as patients with bad results may have refrained from further follow-up. Long-term follow-up is necessary.

Acrylic Resins↗

PubMed2005

Efficacy and safety of polyacrylamide hydrogel for facial soft-tissue augmentation.

BACKGROUND: Polyacrylamide is a nonabsorbable soft-tissue filler that has been used for body contouring for more than 10 years. Aquamid is a soft-tissue filler containing polyacrylamide hydrogel. Safety and aesthetic results after injection of polyacrylamide hydrogel for facial soft-tissue enhancement were assessed at a 1-year follow-up. METHODS: In a prospective, multicenter study, 251 patients were enrolled and assigned for injection of polyacrylamide hydrogel (Aquamid) as a means of facial augmentation and enhancement of facial contours. Subjects with facial contour deformities or soft-tissue deficiencies caused by aging, acne, trauma, surgery, or other causes were included. Persons presenting with connective tissue disorders, skin disorders affecting the face, uncontrolled diabetes mellitus, compromised immune functions or acute inflammatory diseases, known substance abuse, or mental disorders were excluded from participation in the study, as were those who had experienced treatment with any nonabsorbable filler within 6 months before the start of the study. To assess the safety and efficacy of the treatment, follow-up visits were scheduled for day 7, day 28, and 3 months, 6 months, and 12 months after the first injection. Standardized photographs were taken before treatment and during month-3 and month-12 visits. Blood and urine samples were collected and analyzed before injection and at 6 and 12 months after injection. The most common sites of injection were the nasolabial folds (48 percent) and lips (25 percent) followed by glabella folds (8 percent) and other sites. The amount of injected gel ranged from 0.2 to 12 ml. RESULTS: Two hundred twenty-eight patients were followed for 12 months after treatment. In 93 percent, results were judged to be good or very good by the investigators and satisfactory or very satisfactory by the patients. Adverse events that could be ascribed to the treatment were observed in 37 cases, most commonly presenting as transient swelling, hematoma, redness, and pain or itching. In one case, a slight change of skin color at the site of injection was reported. No severe adverse events related to the gel were observed. In one case, neutropenia was detected in month-12 blood samples. The other values were within the normal ranges. CONCLUSIONS: Aquamid is an easy-to-use soft-tissue filler. The effect of tissue enhancement lasted over the entire study period. Transient local tissue reactions observed were attributable to the injection procedure rather than the chemical properties of the gel. During the first year after treatment, no permanent soft-tissue reaction was observed. Long-term results need to be evaluated in the future.

Acrylic Resins↗

PubMed2005

Oxygen consumption in undifferentiated versus differentiated adipogenic mesenchymal precursor cells.

To date, no adequate implant material for the correction of soft tissue defects such as after extensive deep burns, tumor resections or in congenital defects is available. A biohybrid composed of viable adipose precursor cells and an optimised matrix could help towards a solution. Morphologically, preadipocytes resemble fibroblasts and have not yet built a large cytoplasmic lipid droplet as found in differentiated adipocytes. Additionally, preadipocytes are smaller than mature adipocytes allowing a quicker revascularization after transplantation. Furthermore, transplanted preadipocytes can form adipose tissue in vivo whereas the transplantation of mature adipocytes often gives poor results, i.e. oil cysts or shrinkage of the transplant. Since these observations point to differences in metabolic activity between preadipocytes and adipocytes, we investigated the oxygen consumption of preadipocytes stimulated to undergo differentiation, and fibroblasts, by measuring the respiration with a Clark-type oxygen electrode. Preadipocytes had a significantly lower oxygen consumption than mature adipocytes. This advantage in respiration and the better revascularization of undifferentiated adipose tissue cells allow the development of innovative transplants and point to preadipocytes as promising tool to improve transplantations in adipose tissue reconstruction.

3T3 Cells↗

PubMed2005

Abrogation of transforming growth factor-beta signaling by SMAD7 inhibits collagen gel contraction of human dermal fibroblasts.

Human fibroproliferative disorders like hypertrophic scarring of the skin are characterized by increased contractility and excess extracellular matrix synthesis. A beneficial role of transforming growth factor (TGF)-beta in wound healing was proposed; however, chronic stimulation by this cytokine leads to fibrosis. In the present report, the intracellular TGF-beta signaling in fibroblasts derived from hypertrophic scars and normal skin was examined. In an attempt to intervene in profibrogenic TGF-beta functions, ectopic expression of Smad7 or dominant negative Smads3/4 completely inhibited contractility of scar-derived and normal fibroblasts after suspension in collagen gels. Both cell types displayed constitutive Smad2/3 phosphorylation and (CAGA)9-MLP-Luc activity with expression and phosphorylation of Smad3 being predominant in hypertrophic scar-derived fibroblasts. Down-regulation of intrinsic signaling with various TGF-beta antagonists, e.g. soluble TGF-beta receptor, latency-associated peptide, and anti-TGF-beta1 antibodies, confirms autocrine TGF-beta stimulation of both cell populations. Further, Smad7 expression inhibited alpha1 (I) collagen and alpha-smooth muscle actin expression. In summary, our data indicate that autocrine TGF-beta/Smad signaling is involved in contractility and matrix gene expression of fibroblasts from normal and hypertrophic scars. Smad7 inhibits these processes and may exert beneficial effects on excessive scar formation.

Actins↗

PubMed2005

Implantation of preadipocyte-loaded hyaluronic acid-based scaffolds into nude mice to evaluate potential for soft tissue engineering.

The reconstruction of soft tissue defects following extensive deep burns or tumor resections remains an unresolved problem in plastic and reconstructive surgery since adequate implant materials are still not available. Preadipocytes, immature precursor cells found between mature adipocytes in adipose tissue, are a potential material for soft tissue engineering since they can proliferate and differentiate into adipose tissue after transplantation. In previous studies, we identified hyaluronan benzyl ester (HYAFF 11) sponges to be promising carrier matrices. This study now evaluates, in vitro and in vivo, a new sponge architecture with pores of 400 microm either made of plain HYAFF 11 or HYAFF 11 coated with the extracellular matrix glycosaminoglycan hyaluronic acid. Human preadipocytes were isolated, seeded onto carriers and implanted into nude athymic mice. Explants harvested after 3, 8, and 12 weeks were examined for macroscopical appearance, thickness, weight, pore structure, histology, and immunohistochemistry. Compared to previous studies, we found better penetration of cells into both types of scaffolds, with more extensive formation of new vessels throughout the construct but with only minor adipose tissue. Our encouraging results contribute towards a better seeded and vascularised scaffold but also show that the enhancement of adipogenic conversion of preadipocytes remains a major task for further in vivo experiments.

Adipocytes↗

PubMed2005

The single and double-folded supraclavicular island flap as a new therapy option in the treatment of large facial defects in noma patients.

BACKGROUND: Noma is a disfiguring disease requiring a complex therapeutic strategy involving a range of approaches, from skin grafts to local flaps, pedicled flaps, and free flaps. The surgeon must adapt his or her choice of therapy to the patient and, especially in the Third World, to local healthcare environments. METHODS: The authors describe 10 case reports from a stay at the Noma Children's Hospital, in Sokoto, Nigeria, where they used the supraclavicular island flap as a new therapy option for the reconstruction of large facial defects resulting from noma infection. In combination with local mucosa or skin grafts, the supraclavicular island flap was used as an outer lining and also, in three cases, as an inner lining in the form of a double-folded flap. RESULTS: The authors were able to use a pedicled supraclavicular island flap to cover defects as large as half of the face. All 10 pedicled supraclavicular island flaps survived; the only exception was a partial flap necrosis resulting from incorrect application of a wound dressing that kinked the pedicle of the flap. CONCLUSIONS: The authors recommend consideration of the supraclavicular island flap in combination with mucosal or skin grafts as a reliable and safe option for covering most facial defects in noma patients. Because of its simplicity and reliability, this flap replaced the deltopectoral flap and the latissimus dorsi flap as "workhorses," actually reducing the indication for free flaps to the face in cases of large full-size defects. Double folding the supraclavicular island flap is possible, but further clinical studies are needed.

Acute Disease↗

PubMed2005

Pre-expanded ultra-thin supraclavicular flaps for (full-) face reconstruction with reduced donor-site morbidity and without the need for microsurgery.

BACKGROUND: The expanded supraclavicular island flap, as described in 1997 by the senior author (Pallua), is a useful tool for total facial reconstruction, providing satisfactory results without microsurgical prefabrication. The authors report the use of this technique in 12 patients requiring large flaps who presented with extensive facial scarring that had been previously reconstructed using disfiguring, pigmented skin grafts. METHODS: On the basis of their anatomical dissection studies and knowledge of the constant anatomy of the supraclavicular artery and two draining veins, the authors carefully inserted tissue expanders under the supraclavicular island flaps. After the flaps were expanded, all scars were removed and the covering flaps were transferred into place. Sixteen pre-expanded supraclavicular island flaps were used in 11 patients. RESULTS: There were no complications. CONCLUSIONS: The authors present a method of facial reconstruction that has the advantages of creating a large amount of thin tissue of both good color and texture, without the disadvantages of donor-site morbidity, lengthy operative time, and high cost. In their opinion, this is the method of choice for total facial reconstruction.

Adolescent↗

PubMed2005

Effect of chronic wound exudates and MMP-2/-9 inhibitor on angiogenesis in vitro.

BACKGROUND: New evidence suggests that matrix metalloproteinases (MMPs) may facilitate angiogenesis as well as function to generate angiogenesis inhibitors. In this study, the angiogenic effect of wound exudates from patients with venous insufficiency ulcers was examined in an in vitro angiogenesis model with and without synthetic MMP-2/-9 inhibitor. METHODS: Wound exudates were obtained from 20 patients with venous insufficiency ulcers and 20 control patients with donor-site wounds after skin grafting for burns. In the angiogenesis model, suramin (20 microg/ml) was used in five wells without wound fluid as negative control, and vascular endothelial growth factor (1 microg/ml) was used in five other wells as positive control. Chronic wound fluids were analyzed without and with a synthetic MMP-2/-9 inhibitor with a concentration of 2 microM and 20 microM in the medium. The total length of tubules was calculated by map reader. Statistical analysis was performed using the Mann-Whitney test. The level of significance was considered to be p < 0.05. RESULTS: Chronic ulcer exudates inhibited angiogenesis significantly (490 +/- 130 microm) compared with acute wound fluids (1740 +/- 320 microm; p < 0.05). In wells with chronic wound exudates and high concentrations of MMP-2/-9 inhibitor, angiogenesis was stimulated significantly (870 +/- 220 microm, p < 0.05). CONCLUSIONS: In this model, reduced angiogenesis might be due to an antiangiogenic effect of MMP-2 and MMP-9. MMP-2/-9 inhibition results in a stimulation of angiogenesis and might be an approach for the treatment of patients with chronic wounds and reduced angiogenesis.

Aged↗

PubMed2005

Duplex ultrasound imaging in free transverse rectus abdominis muscle, deep inferior epigastric artery perforator, and superior gluteal artery perforator flaps: early and long-term comparison of perfusion changes in free flaps following breast reconstruction.

OBJECTIVE: Our objective was to assess the hemodynamic differences in free DIEP (deep inferior epigastric artery perforator flap), S-GAP (superior gluteal artery perforator flap) flaps versus TRAM (transverse rectus abdominis muscle) flaps and to analyze any perfusion change due to perforator dissection (study 1). To examine the hypothesis as to whether flap perfusion is maintained through the pedicle (study 2), we also compared short- and long-term DIEP flap perfusion. MATERIAL AND METHODS: Blood volume flow, velocity, and diameter of the donor and recipient vessels of 4 TRAM flaps, 5 S-GAP flaps, and 17 DIEP flaps were examined preoperatively on day 5 and also 18 months postoperatively using duplex ultrasound. RESULTS: The greatest volume flow and velocity are measured in the TRAM flaps, followed by S-GAP and DIEP flaps. Blood flow in the musculocutaneous and perforator flaps is twice as great as in the donor vessels, which is proof of flap hyperperfusion. SUMMARY: The minimum perfusion requirement is easily satisfied in musculocutaneus and free perforator flaps. In the long term, DIEP flap perfusion increases 13%, which assumes that DIEP flap perfusion is maintained on the pedicle.

Anastomosis, Surgical↗

PubMed2005

Severe burns as a consequence of seizure while showering: risk factors and implications for prevention.

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Adolescent↗

PubMed2005

Optimization of the differentiation of human preadipocytes in vitro.

This study aimed at developing an optimal protocol for proliferation and differentiation of preadipocytes that is a prerequisite for constructing an ideal biohybrid composed of viable adipose precursor cells in a three-dimensional matrix. Such an implant could represent an adequate solution for correcting soft tissue defects, e.g., extensive deep burns or tumor resections. Preadipocytes were isolated from human subcutaneous adipose tissue samples and cultured in Dulbecco's modified eagle medium (DMEM)/Ham's F12 medium (F12) or OPTIMEM medium with or without the addition of human serum (hS) or fetal calf serum (FCS). The advantages of fibronectin-coated culture dishes for preadipocyte yield after isolation and differentiation were evaluated. After culture expansion, differentiation was induced by insulin, isobutylmethylxanthine, pioglitazone, dexamethasone, and transferrin in the absence of serum. The extent of differentiation was assayed by measuring the activity of glycerophosphate dehydrogenase as well as counting of differentiated versus undifferentiated cells. Our results show that fibronectin coating does not only strongly increase the yield of preadipocytes after isolation from adipose tissue but also significantly enhances differentiation of precursor cells to mature adipocytes. For optimal cell expansion, DMEM/F12 is more promoting than OPTIMEM and culturing with FCS shows a slightly better proliferation compared with hS supplementation. Differentiation, in contrast, is significantly improved when hS is used instead of FCS during proliferation. Our results smooth the way for autologous preadipocyte culturing and show that hS for preadipocyte culturing opens new and promising perspectives for adipose tissue engineering by optimizing in vitro expansion in cell culture and inducing substantial differentiation.

Adipocytes↗

PubMed2005

Adaptive soft tissue deformation for a virtual reality surgical trainer.

Real time tissue deformation is an important aspect of interactive virtual reality (VR) environments such as medical trainers. Most approaches in deformable modelling use a fixed space discretization. A surgical trainer requires high plausibility of the deformations especially in the area close to the instrument. As the area of intervention is not known a priori, adaptive techniques have to be applied. We present an approach for real time deformation of soft tissue based on a regular FEM mesh of cube elements as opposed to a mesh of tetrahedral elements used by the majority of soft tissue simulators. A regular mesh structure simplifies the local refinement operation as the elements topology and stiffness are known implicitly. We propose an octree-based adaptive multiresolution extension of our basic approach. The volumetric representation of the deformed object is created automatically from medical images or by voxelization of a surface model. The resolution of the volumetric representation is independent of the surface geometry resolution. The surface is deformed according to the simulation performed on the underlying volumetric mesh.

Computer Simulation↗

PubMed2004

Matrix metalloproteinases, tissue inhibitors of metalloproteinases, aminoterminal propeptide of procollagen type III, and hyaluronan in sera and tissue of patients with capsular contracture after augmentation with Trilucent breast implants.

In various fibrotic diseases, matrix metalloproteinases (MMPs) and their natural inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), play an important role. In our study, serum concentrations of MMP-1, MMP-2, MMP-9, TIMP-1, and TIMP-2 were determined by enzyme-linked immunosorbent assay in 17 female patients with Baker grade II (n =9), III (n =7), and IV (n =1) capsular contracture after bilateral cosmetic mamma augmentation with Trilucent implants (AEI, Inc., Caversham, United Kingdom). Samples of capsular tissue for standard histology and immunohistochemistry were obtained from all patients. Sera from 20 female patients who had plastic surgery for reduction mammaplasty were used as the control group. The aminoterminal propeptide of procollagen type III (PIIINP) and hyaluronan were analyzed as markers for fibrogenesis in both groups, too. Statistical analysis was performed using the Mann-Whitney test and Spearman rank correlation. Patients with capsular contracture presented significantly higher concentrations of TIMP-1 and TIMP-2 in their sera than did the control group (p < 0.05), which correlated with Baker grade (r = 0.7 versus r = 0.65; p < 0.05). The concentration of MMP-2 was significantly higher in the sera of patients with capsule fibrosis, whereas there were no significant differences in MMP-1, MMP-9, and PIIINP serum concentrations. Patients with capsule fibrosis had a significantly lower MMP-to-TIMP ratio (1.1 +/- 0.4, p <0.05) than the control group (1.5 +/- 0.4), which correlated with the Baker classification (r =0.7; p <0.05). The hyaluronan serum concentration of patients with capsular contracture was significantly higher (p < 0.05) and correlated with the Baker grade (r = 0.73; p < 0.05), whereas PIIINP showed no difference. In the histologic evaluation, there was a chronic inflammatory reaction in the capsules around the breast implants and refracting material within the substance. Immunohistochemically, TIMP-1 and TIMP-2 showed an intensive accumulation, and MMP-2 showed a local reaction. PIIINP could be detected, too, whereas there was no staining for MMP-1 and MMP-9. The elevated systemic MMP-2 concentration and the local positive staining in the tissue might be due to the chronic inflammatory reaction. Nevertheless, the balance between MMPs and their natural inhibitors is disturbed in patients with capsule contracture. The elevated systemic concentration of TIMPs might be a pathway in the pathogenesis of severe fibrosis after breast augmentation with alloplastic material. Hyaluronan might be a useful marker for early prediction of capsule fibrosis, whereas PIIINP is not useful as a predictor.

Adult↗

PubMed2004

Comparison of viable cell yield from excised versus aspirated adipose tissue.

The correction of soft-tissue defects by adipose tissue transplantation often produces poor and unpredictable results. The implantation of isolated and cultured preadipocytes offers a solution to this problem since these cells differentiate into adipocytes when implanted in vivo. A field of major interest is to maximize the yield of preadipocytes isolated from adipose tissue showing only low contamination with other cell types. Aspiration and excision are two concurrent clinical ways of harvesting adipose tissue for the isolation of preadipocytes. This tissue is usually discarded after surgery. In this study, the yield of preadipocytes obtained from liposuction material was compared to that of excised adipose tissue. Furthermore, we determined the loss of precursor cells if isolation of preadipocytes was delayed for 24 h. Preadipocytes were isolated from the stromal cell fraction of human subcutaneous adipose tissue samples. Harvesting of adipose tissue by suction was performed according to the Coleman procedure (manually applied negative pressure using a 10-ml syringe with a blunt tip cannula). Isolation was either carried out within 60 min after extraction or after storage for 24 h in culture medium at 4 degrees C. Isolated preadipocytes were cultured for 24 h, trypsinized and counted in a Neubauer chamber. Our results show clearly that the yield of preadipocytes isolated from liposuction material (within 60 min after extraction and after 24 h of storage) is higher than the cell yield from excised adipose tissue. Overnight storage for 24 h leads to a significant loss of preadipocytes in excised tissue but not in liposuction material. The high yield of cells isolated from liposuction material proves that extraction by suction does not damage the stromal cell fraction in the adipose tissue. If cell isolation is not performed immediately after the operation, liposuction material is clearly the better alternative for storage.

Adipocytes↗

PubMed2004

Modification of collagen matrices for enhancing angiogenesis.

The vascularization of engineered tissues in many cases does not keep up with the ingrowth of cells. Nutrient and oxygen supply are not sufficient, which ultimately leads to the death of the invading cells. The enhancement of the angiogenic capabilities of engineered tissues therefore represents a major challenge in the field of tissue engineering. The immobilization of angiogenic growth factors may be useful for enhancing angiogenesis. The most potent angiogenic growth factor specific to endothelial cells, vascular endothelial growth factor (VEGF), occurs in several splice variants. The variant with 165 amino acids both has a high angiogenic activity and a high affinity for heparin. We therefore incorporated heparin molecules into collagen matrices by covalently cross-linking them to amino functions on the collagen. Physical binding of VEGF to the heparin may then prevent a rapid clearance from the implant, while the release rate may become coupled to the degradation of the collagen matrix. The modified matrices were characterized by determination of the extent of the heparin immobilization, the in vitro degradation rate by collagenase. For testing the angiogenic properties, non-modified and heparinized collagen specimens were--either loaded with VEGF or non-loaded--subcutaneously implanted on the back of rats. Specimens were explanted after varying periods of implantation, the dry weights and the hemoglobin contents, as well as immunostained histological sections were evaluated: heparinized collagen matrices loaded with VEGF are vascularized to a substantially higher extent as compared to non-modified matrices.

Angiogenesis Inducing Agents↗

PubMed2004

Influence of low frequency electric fields on anti- and pro-coagulability of the vascular endothelium: new insights into high-voltage electrical injury.

After high-voltage electric injury, patients often show tissue necrosis and thrombosis of blood vessels even remote from entry and exit site of electrical current. In this study, plasma levels of TAT, F(1+2), PAI-1, and t-PA were determined in vivo in three patients with high-voltage injury for 96 hours after trauma. In order to analyse a possible effect on haemostasis related to endothelial cell damage, protein S, TF, ET-1, PGI(2), NO, t-PA, and PAI-1 were determined for 72 hours in vitro in cell culture supernatant of HUVECs that had been exposed to 1, 10, 30, and 50 electric field periods of 50 Hz with field strength of 60 V/cm and duration of 20 ms. Furthermore, expression of thrombomodulin was immunohistochemically analysed. Clotting activation could be observed in our patients by increased levels of F(1+2) and TAT between 12 and 72 hours after injury, whereas fibrinolysis was disturbed due to high PAI-1. One patient presented thrombosis of vessels by day 3. In vitro, PAI-1 increased significantly (p<0.05) in medium of cells with an application of 30 and 50 periods between 2 and 48 hours. Between 4 and 72 hours, the concentration of t-PA was significantly lower (p<0.05) in the medium of HUVECs exposed to 10, 30, and 50 periods, whereas there was a significant increase (p<0.05) in the concentration of TF in the cell groups with an application of 30 and 50 periods. 24, 48, and 72 hours after injury, there was just weak or no staining for thrombomodulin in HUVECs with an application of 30 and 50 periods. The disturbed balance between clotting system and fibrinolysis seen in vitro after electric injury might explain the clinical observation of a progressive thrombosis of blood vessels after electric injury leading to tissue loss.

Adolescent↗

PubMed2003

TIMP-1, MMP-2, MMP-9, and PIIINP as serum markers for skin fibrosis in patients following severe burn trauma.

The wound-healing process of patients with severe burns often leads to the formation of extensive fibrotic scars. In this study, serum concentrations of tissue inhibitors of metalloproteinase-1 (TIMP-1), matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and amino-terminal propeptide of procollagen type III (PIIINP) were measured by enzyme-linked immunosorbent assay as markers for excessive cicatrization in 22 patients with acute burn injuries. All patients were followed up for 6 months to determine a fibrotic reaction during the wound-healing process after operative treatment using the Burn Scar Index. Blood samples were drawn immediately before the operation; at postoperative days 1, 3, 7, and 14; and 1, 3, and 6 months after the operation. Twenty patients who underwent elective plastic surgical operations served as the control group. There was a significant increase (p < 0.05) of TIMP-1 in the burned patients by the third postoperative day. Later in the follow-up period, the serum concentrations remained at a significantly elevated level (p < 0.05) compared with preoperative values. In comparison with the control group, the postoperative serum concentrations of TIMP-1 of the burned patients were significantly higher (p < 0.05) at any time and correlated with the total body surface area burned at the third and seventh postoperative days (p < 0.05; r2 = 0.46 versus r2 = 0.53) and the Burn Scar Index after 6 months (p < 0.05; r2 = 0.65). Serum levels of MMP-2 and MMP-9 showed a significant elevation (p < 0.05) only between postoperative days 3 and 14 in patients with burn wounds. PIIINP increased significantly (p < 0.05) in the sera of the burned patients at postoperative day 3 and remained significantly elevated up to 6 months after injury. At any time after trauma, PIIINP serum levels were significantly higher (p < 0.05) in the burned patients than in the control group and correlated with the total body surface area burned at postoperative days 3 and 7 (p < 0.05; r2 = 0.41 versus r2 = 0.44) and the Burn Scar Index after 6 months (p < 0.05; r2 = 0.5). Obviously, the physiological balance between matrix metalloproteinases and their endogenous inhibitors is disturbed after burn trauma. The elevated systemic TIMP-1 concentration might contribute to tissue fibrosis, leading to pathological scar formation. The increase of PIIINP after thermal trauma indicates a fibrogenic component of wound healing.

Biomarkers↗